Bis-pyrene carbocations for chromogenic and fluorogenic dual-detection of fluoride anion in situ

Pyrene-Based AIE Active Materials for Bioimaging and Theranostics Applications

Aggregation-induced emission (AIE) is a unique research topic and property that can lead to a wide range of applications, including cellular imaging, theranostics, analyte quantitation and the specific detection of biologically important species. Towards the development of the AIE-active materials, many aromatic moieties composed of tetraphenylethylene, anthracene, pyrene, etc., have been developed. Among these aromatic moieties, pyrene is an aromatic hydrocarbon with a polycyclic flat structure containing four fused benzene rings to provide an unusual electron delocalization feature that is important in the AIE property. Numerous pyrene-based AIE-active materials have been reported with the AIE property towards sensing, imaging and theranostics applications. Most importantly, these AIE-active pyrene moieties exist as small molecules, Schiff bases, polymers, supramolecules, metal-organic frameworks, etc. This comprehensive review outlines utilizations of AIE-active pyrene-based materials on the imaging and theranostics studies. Moreover, the design and synthesis of these pyrene-based molecules are delivered with discussions on their future scopes.

Photocytotoxicity of heavy-atom-free thiobarbituric acid functionalized pyrene derivatives against MCF-7 cancer cells

Two thiobarbituric acid-functionalized pyrene derivatives (P1, P2) have been synthesized to explore the photophysical properties and photodynamic activity of dyes of this type. Both compounds exhibit an intense intramolecular charge transfer (ICT) band at ca. 470 nm, which is absent in the spectra of the precursor. P1 and P2 exhibit singlet oxygen generation on irradiation with light with moderate singlet oxygen yields of 0.36 and 0.32, respectively, in DMSO. P1 showed better photodynamic activity against MCF-7 cells with an IC₅₀ value of 18.3 μM under illumination at 455 nm for 60 min with a Thorlabs M455L3 LED (330 mW.cm^-2).

An in Situ Intracellular Self-Assembly Strategy for Quantitatively and Temporally Monitoring Autophagy

Autophagy plays a crucial role in the metabolic process. So far, conventional methods are incapable of rapid, precise, and real-time monitoring of autophagy in living objects. Herein, we describe an in situ intracellular self-assembly strategy for quantitative and temporal determination of autophagy in living objectives. The intelligent building blocks (DPBP) are composed by a bulky dendrimer as a carrier, a bis(pyrene) derivative (BP) as a signal molecule, and a peptide linker as a responsive unit that can be cleaved by an autophagy-specific enzyme, i.e., ATG4B. DPBP maintains the quenched fluorescence with monomeric BP. However, the responsive peptide is specifically tailored upon activation of autophagy, resulting in self-aggregation of BP residues which emit a 30-fold enhanced fluorescence. By measuring the intensity of fluorescent signal, we are able to quantitatively evaluate the autophagic level. In comparison with traditional techniques, such as TEM, Western blot, and GFP-LC3, the reliability and accuracy of this method are finally validated. We believe this in situ intracellular self-assembly strategy provides a rapid, effective, real-time, and quantitative method for monitoring autophagy in living objects, and it will be a useful tool for autophagy-related fundamental and clinical research.

Fluoride-specific fluorescence/MRI bimodal probe based on a gadolinium(iii)–flavone complex: synthesis, mechanism and bioimaging application in vivo

The present work reports a bimodal probe for the fluorescence and magnetic resonance detection of fluoride ion (F⁻) in aqueous medium andin vivo.

A highly selective colorimetric chemosensor for detection of iodide ions in aqueous solution

A simple chemosensor can be used as a colorimetric sensor for the highly selective and sensitive detection of iodide anions in aqueous solution.

Pyrene Based Chemosensor for Selective Sensing of Fluoride in Aprotic and Protic Environment

A new aromatic hydrazone based on pyrene-1-aldehyde was synthesized and characterized by (1)H NMR and mass spectrometric analyses. The sensing properties of the hydrazone were studied by absorption and fluorescence studies in the aprotic solvent DMSO. It was capable of visual and fluorescent detection of fluoride over competitive ions (Cl(-), Br(-), H2PO4 (-), AcO(-)). Moreover, the in-situ prepared iron(III) complex of the hydrazone was investigated as a turn off fluorescent fluoride sensor in aqueous medium by displacement mechanism.

A highly selective and sensitive fluorescence “turn-on” fluoride ion sensor

A highly selective and sensitive fluorescence “turn-on” and colorimetric dual-channel fluoride ion sensor.